In practice it does feel like basically every single Amtrak is delayed after just a few stops, so I would be shocked if the situation is worse in Germany. However to put some numbers on it, here are Amtrak's own stats: https://www.bts.gov/content/amtrak-time-performance-trends-a.... In the flagship northeast corridor (that's Boston - NYC - Philadelphia - DC) the "on-time" percentage is around 80%, where on-time is within 20 minutes.
In the rest of the country Amtrak blames freight companies for most delays (https://www.amtrak.com/on-time-performance), and frankly I am inclined to agree with them. Amtrak does not own those lines and does not have priority on them, and the freight companies don't give a shit about anyone. See for example https://www.propublica.org/article/trains-crossing-blocked-k... and the rest of ProPublica's excellent series on the industry.
Agreed, I just think it's worth mentioning because a lot of the discussion in this thread is about how much Deutsche Bahn sucks, and while Amtrak also sucks, it doesn't suck quite as much as experience would lead you to believe. Much of the blame is on America as a whole, not specifically Amtrak.
Or to put it another way, it sounds like DB has a lot of problems that it could fix, but Amtrak has a lot of problems that are out of its control.
